Manufacture of viscose rayon



Patented Oct. 23, 1951 MANUFACTURE OF VISCOSE RAYON Gilbert I. Thurmond,Asheville, N. 0., assignor to American Enka Corporation, Enka, N. 0., a

corporation of Delaware- No Drawing. Application January 23, 1950.Serial No. 140,149

11 Claims.

a process involving the addition of surface active agents to the viscosesolution and to the acid coagulating bath in order to improve the char--acteristics of the finished product and to improve the spinningconditions generally.

It is known to add anion active compounds such as highly sulphonatednon-mineral oils of the type sold under the trade-name Prestabit Oil toviscose solutions in order to inhibit turbidity or milkiness in therayon. (See U. S. Patents Nos. 1,925,192 and 1,936,479.) While thesecompounds are effective in this respect; they, as well as all anionactive materials have a tendency to promote clogging of spinneretorifices. .It was not until the use of cation active compounds (see U.S. Patent No. 2,125,031) was commenced that spinneret clogging wassubstantially prevented.

Thus, in order to improve both the yarn and the spinning conditions ithas been necessary to add an anion active compound to the viscosesolution and a cation active compound to the acid spinbath. This isobviously objectionable because the two classes of materials come incon-v tact with one another during the spinning operation and have atendency toward compound formation and mutual precipitation. Inaddition,

the anion active compound in the viscose may -counteract or retard theeffectiveness of the cation active compound in the spinbath with respectto spinneret incrustation.

Accordingly, on a theoretical basis it would be more feasible to useeither one or more anion active compounds or One or more cation active;compounds in both the viscose solution and spinbath. However, since itis known that anion active materials cannot be used in the spinbath forpractical reasons, it is necessary that the material common to both theviscose solution and the spinbath be cationic in character.

It is therefore the object of the present invention to provide a cationactive compound that serves both the purpose of inhibiting milkiness inthe viscose yarn and reducing spinneret incrustation in the spinbath.

Another object of this invention is to use small amounts of a cationactive compound either in the viscose solution whereby it will get intothe spinbath'during the spinning operation, or add it directly to thespinbath in addition to adding it to the viscose.

A further object of the invention is to utilize a particular class ofcation active compounds that k are good dispersants and are sufiicientlysoluble and stable in both alkali and viscose to prevent 'milkiness inthe yarn while at the same time are sufficiently soluble and stable inthe acid spinbath to prevent spinneret incrustation.

It has now been determined that if a long chain aliphatic primary amineis caused to react with an alkylene oxide such as ethylene oxide to forma tertiary amine, its properties can be modified to the extent ofrendering it suitable for preventing or inhibitingmilkiness in the yarnwhile at the same time reducing spinneret incrustation. By controllingthe length of the alkylene oxide chains, derivatives can be preparedthat are soluble and stable in both the alkaline viscose solution andthe acid spinbath. The necessary length of the alkylene oxide chains isdependent on the length of the alkyl group in the amine because thehydrocarbon group becomes more hydrophobic as the chain length increaseswhereas the alkylene oxide chain becomes more hydrophilic as the chainlength increases. Therefore, it is only necessary to control the lengthof the alkylene oxide chain so that it predominates over the alkyl groupin the amine whereby the condensate is rendered sufficiently soluble inan aqueous solution to be effective for the purposes here involved.

Compounds of this type are known in the trade as Ethomeens and reactionproducts of long chain aliphatic primary amines with ethylene oxide, thereaction being represented generally as follows:

}OY.H2HO)=H RNHQ (z monaho RN (CflHnOMH In the above formula, Rrepresents an aliphatic chain having from 8 to 24 carbon atoms thereinand preferably from 12 to 14 carbon atoms. a; or y is at least one, andr-l-y is the total number of alkylene oxide chains which may be as lowas 5 without any definite restriction on the upper limit although 12 to18 or about 15 have been found .to be quite effective, and n is a smallwhole number from 2 to 4, both inclusive.

Specific Ethomeens which have proved very effective in preventingmilkiness and spinneret incrustation are known as Ethomeen 0/25 andEthomeen 8/25. Resolving these into their structural formulate theextent possible they are:

The length of the aliphatic chain R depends on the oil from which theparent amine is prepared,

fwith.

which in the case of C/25 is coco and 5/25 is soya. In both cases molesof ethylene oxide are added to the amine. The ethylene oxide apparentlyseparates fortuitously into two chains designated as a: and y to formthe tertiary amine. It has been demonstrated that the second mole ofethylene oxide is more strongly attracted to the amino nitrogen than itis to the hydroxyl group so that a bishydroxy ethyl alkyl amine isformed. After a total of 5 moles of ethylene oxide had been added to theprimary amine it was determined that it had been over 99% converted intoa tertiary amine. Therefore, theoretically, the reaction product maycontain as low as 5 moles of ethylene oxide provided the solubility issufficient in alkali and acid although thus far it has been determinedfor optimum results, about 15 moles of ethylene oxide are required forthe reaction.

In accordance with the invention the long chain aliphatic tertiaryamine-alkylene oxide condensate is added in small quantities, e. g.,0.12% to 0.24% based on the weight of cellulose to the viscose and, ifrequired, lesser amounts to the acid spinbath based on the weight of thespinbath,

of course taking the necessary precautions to insure an .even anduniform admixture there- In practice, it has been determined thatcertain advantages are realized if the condensate is added in thepremanufacturing stages, e. g., during the shredding operation wherebythe alkali cellulose-appears to become more flufiy which enhancessubsequent treating operations.

After the addition of the condensate the viscose' is otherwise preparedin the normal manner and thereafter extruded through minute spinneretorifices into an acid spinbath to form filaments and the like therefrom.It was determined on examination of the finished rayon that it was 1-more 'efiective than Prestabit Oil in preventing inilkiness, even whenfive times as much Prestibit Oil was used. Furthermore, it was quiteefiective in inhibiting spinneret incrustation.

Experiments were conducted with respect to solubility and stability ofEthomeen (3/25 and 58/25 in acid and alkali using 2.0% solutions. .Theresults are tabulated as follows:

From the above it can be concluded that the compounds in question areadequately soluble and stable in both media.

In conducting several comparative tests for milkiness reduction,Ethomeen C/ and S/25 were added to the viscose in 0.12% and 0.24%quantities based on the weight of cellulose. These viscoses were spun inthe normal manner at the normal maturity of 9.8 and at a higher maturityof 11 to 11.5. On examination of the finished rayon it comparedfavorably with, or was even superior in appearance to, rayon containingPrestabit Oil. 3 I g When the Ethomeens were added to the viscose in theabove mentioned quantities and the viscose was spun in an acid spinbathcontaining cation active. material, it was determined that the pressurebuild-up behind the spinnerets was reduced markedly, indicatingexcellent inhibition of spinneret incrustation. This was confirmed bysubsequent microscopic examination of the spinnerets.

It can be seen that the use of small amounts of long chain aliphatictertiary amine-ethylene oxide condensates in accordance. with thisinvention produces several important advantages in the manufacture ofviscose rayon. The invention is therefore not to be limited in an mannerother than by the scope defined in the appended claims.

What is claimed is:

1. In the manufacture of viscose yarn wherein a viscose solution isextruded through minute orifices into an acid spinbath to form filamentsand the like therefrom, the step which comprises spinning the viscosefilaments in the presence of a long chain aliphatic tertiaryaminealkylene oxide condensate formed from the reaction of a lon chainaliphatic primary amine with an alkylene oxide whereby milkiness in thefilaments and incrustation. of the orifices are inhibited.

2. In the manufacture of viscose yarn wherein a viscose solution isextruded through minute orifices into an acid spinbath to form filamentsand the like therefrom, the step which comprises spinning the viscosefilaments in the presence of a small amount of a long chain aliphatictertiary amine-alkylene oxide condensate formed from the reaction of along chain aliphatic primary amine with an alkylene oxide wherebymilkiness in the filaments and incrustation of the orifices areinhibited.

3. In the manufacture of viscose yarn wherein a viscose solution isextruded through minute orifices into anacid spinbath to form filamentsand the like therefrom, the step which comprises spinning the viscosefilaments in the presence of 0.12% to 0.24% based on the weight of thecellulose of a lon chain aliphatic tertiary aminealkylene oxidecondensate formed from the reactionof a long chain aliphatic primaryamine with an alkylene oxide whereby milkiness in the fila- -ments andincrustation of the orifices are inhibited.

4. In the manufacture of viscose yarn wherein a viscose solution isextruded through minute orifices into an acid spinbath to form filamentsand the like therefrom, the step which comprises spinning the viscosefilaments in the presence of along chain aliphatic tertiaryamine-ethylene oxide condensate formed from the reaction of a long chainaliphatic primary amine with ethylene oxide whereby milkiness in thefilaments and incrustation of the orifices are inhibited.

5. In the manufacture of viscose yarn wherein a viscose solution isextruded through minute orifices into an acid spinbath to form filamentsand the like therefrom, the step which comprises spinning the viscosefilaments in the presence of a small amount of a long chain aliphatictertiary amine-ethylene oxide condensate formed from the reaction of along chain aliphatic primary amine with ethylene oxide whereby milkinessin the filaments and incrustation of the orifices are inhibited.

6. In the manufacture of viscose yarnwherein a viscose solution isextruded through minute orifices into an acid spinbath to form filamentsand. the like therefrom, the step which comprises spinning the viscosefilaments in the presence of 0.12% to 0.24% based on the weight of thecellulose of a long chain aliphatic tertiary amineethylene oxidecondensate formed from the reaction of a long chain aliphatic primaryamine with ethylene oxide whereby milkiness in the filaments andincrustation of the orifices are inhibited.

7. In the manufacture of viscose yarn wherein a viscose solution isextruded through minute orifices into an acid spinbath to form filamentsand the like therefrom, the step which comprises adding a small amountof a long chain aliphatic tertiary amine-ethylene oxide condensate tothe viscose solution and spinning the same into filaments wherebymilkiness in the filaaments and incrustation of the orifices areinhibited 8. In the manufacture of viscose yarn wherein a viscosesolution is extruded through minute orifices into an acid spinbath toform filaments and the like therefrom, the step which comprises adding0.12% to 0.24% based on the weight of the cellulose of a long chainaliphatic tertiary amine-ethylene oxide condensate to the viscosesolution and spinning the same into filaments whereby milkiness in thefilaments and incrustation of the orifices are inhibited.

9. In the manufacture of viscose yarn wherein a viscose solution isextruded through minute orifices into an acid spinbath to form filamentsand the like therefrom, the step which comprises spinning the viscosefilaments in the presence of a long chain aliphatic tertiaryamine-ethylene oxide condensate formed from the reaction of a long chainaliphatic primary amine with about 15 moles of ethylene oxide wherebymilkiness in the filaments and incrustation of the orifices areinhibited.

10. In the manufacture of viscose yarn wherein a viscose solution isextruded through minute orifices into an acid spinbath to form filamentsand the like therefrom, the step which comprises spinning the viscosefilaments in the presence of a soluble, stable cation active compoundhaving the following formula:

in which R represents an aliphatic chain having at least 8 carbon atomstherein and :c-l-y equals the total number of moles of ethylene oxide atleast 5, fortuitously separated into two chains to form the tertiaryamine whereby milkiness in the filaments and incrustation of theorifices are inhibited.

11. In the manufacture of viscose yarn wherein a viscose solution isextruded through minute orifices into an acid spinbath to form filamentand the like therefrom, the step which comprises spinning the viscosefilaments in the presence of a soluble, stable cation active compoundhaving the following formula:

in which R represents an aliphatic chain having at least 8 carbon atomstherein and x+y equals about 15 moles of ethylene oxide, fortuitouslyseparated into two chains to form the tertiary amine whereby milkinessin the filaments and incrustation of the orifices are inhibited.

GILBERT I. THURMOND.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,174,762 Schuette et a1. Oct. 3,1939 2,214,352 Schoeller et al. Sept. 10, 1940

1. IN THE MANUFACTURE OF VISCOSE YARN WHEREIN A VISCOSE SOLUTION ISEXTRUDED THROUGH MINUTE ORIFICES INTO AN ACID SPINBATH TO FORM FILAMENTSAND THE LIKE THEREFROM, THE STEP WHICH COMPRISES SPINNING THE VISCOSEFILAMENTS IN THE PRESENCE OF A LONG CHAIN ALIPHATIC TERTIARYAMINEALKYLENE OXIDE CONDENSATE FORMED FROM THE REACTION OF A LONG CHAINALIPHATIC PRIMARY AMINE WITH AN ALKYLENE OXIDE WHEREBY MILKINESS IN THEFILAMENTS AND INCRUSTATION OF THE ORIFICES ARE INHIBITED.